Guanethidine Monosulfate
;)
Guanidine,[2-(hexahydro-1(2H)-azocinyl)ethyl]-,sulfate (1:1).
[2-(Hexahydro-1(2H)-azocinyl)ethyl]guanidine sulfate (1:1) [645-43-2].
»Guanethidine Monosulfate contains not less than 97.0percent and not more than 103.0percent of C10H22N4·H2SO4,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Infrared Absorption á197Mñ.
B:
Dissolve 2.5mg in 10mLof water.Add 2mLof a solution prepared by dissolving 500mg of 1-naphthol,3g of sodium hydroxide,and 8g of sodium carbonate in water to make 50mL,and 1mLof a solution of 2,3-butanedione (1in 2000).Allow to stand at room temperature:an intense,pinkish-red color develops.
pHá791ñ:
between 4.7and 5.7,in a solution containing 20mg per mL.
Loss on drying á731ñ—
Dry it at 105
to constant weight:it loses not more than 0.5%of its weight.
to constant weight:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.2%.
Heavy metals,Method IIá231ñ:
0.001%.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Sodium nitroferricyanide–potassium ferricyanide solution—
Dissolve 1g of sodium nitroferricyanide and 1g of potassium ferricyanide in water to make 100mL,and mix.
Standard preparation—
Dissolve a suitable quantity of USP Guanethidine Monosulfate RS,accurately weighed,in 1Nsulfuric acid to obtain a solution having a known concentration of about 1mg per mL.
Assay preparation—
Transfer about 50mg of Guanethidine Monosulfate,accurately weighed,to a 50-mLvolumetric flask,dissolve in 1Nsulfuric acid,add 1Nsulfuric acid to volume,and mix.
Procedure—
Pipet 2mLeach of the Assay preparationand the Standard preparation,and 2mLof 1Nsulfuric acid to provide the blank,into separate glass-stoppered,40-mLcentrifuge tubes.Add 10.0mLof water to each tube,and mix.To each tube add 10.0mLof Sodium nitroferricyanide–potassium ferricyanide solution,mix,add 4.0mLof 1Nsodium hydroxide,mix,and allow to stand for 20minutes,accurately timed.Concomitantly determine the absorbances of both solutions in 1-cm cells against the blank at the wavelength of maximum absorbance at about 500nm,with a suitable spectrophotometer.Calculate the quantity,in mg,of C10H22N4·H2SO4in the Guanethidine Monosulfate taken by the formula:
50C(AU/AS),
in which Cis the concentration,in mg per mL,of USP Guanethidine Monosulfate RSin the Standard preparation,and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5
USP28–NF23Page 932
Phone Number:1-301-816-8305